Movable contact arm assembly



May 26, 1964 c. JENCKS 3,134,878

MOVABLE CONTACT ARM ASSEMBLY Filed July 19, 1962 2 Sheets-Sheet 1 INVENTOR.

CHAR LES L. damcxs AT ORNEY May 26, 1964 c. L. JENCKS MOVABLE CONTACT ARM ASSEMBLY 2 Sheets-Sheet 2 Filed July 19, 1962 INVENTOR.

CHARLES L. daucks BY Wmfifi United States Patent Ofiice 3,134,878 Patented May 26, 1964 3,134,878 MOVABLE CONTACT ARM ASSEMBLY Charles L. .lencks, Avon, Conn, assignor to General Electric Company, a corporation of New York Filed July 19, 1962, Ser. No. 210,919 Claims. (Cl. 206-166) My invention relates to electric circuit breakers and switches, and particularly to movable contact arm assemblies for use in such circuit breakers and switches.

Electric circuit breakers of the type referred to commonly include a plurality of movable contact arms, each including a rigid contact arm and a contact member or contact supporting member pivotally supported on the contact arm. Spring means is provided between the contact supporting member and the contact arm, and means is provided for limiting the movement of the contact supporting member away from the main contact arm.

In accordance with the prior art, the movable contact supporting member has been pivotally supported on the main contact arm by means of an auxiliary bracket, attached to the movable contact supporting member by such means as riveting or welding, or brazing. Such operations add to the expense of manufacture of the circuit breaker, and are also subject to failure in use.

It is an object of the present invention to provide an electric circuit breaker or switching device including a movable contact arm assembly comprising a main contact arm and a movable contact supporting member pivotally supported on the main contact arm by means which does not require any metal-working or other fastening operations.

It is another object of the invention to provide an electric circuit breaker or switching device including a movable contact arm assembly comprising a main contact arm and a movable contact supporting member pivotally supported on the main contact arm by means which is more dependable and less subject to breakage.

In accordance with the invention in one form, an electric circuit breaker is provided comprising a plurality of movable contact assemblies, movable between open and closed circuit positions. Each movable contact assembly comprises a generally channel-shaped contact arm which is pivotally supported in the circuit breaker casing. A movable contact member or contact supporting member is pivotally supported on the main contact arm by means of a U-shaped bracket which straddles the movable contact supporting member. The bracket has bight portion on one side of the movable contact supporting member and has side extensions having a pair of aligned holes, adapted to receive a pivot pin on the opposite side of the movable contact supporting member, The U-shaped bracket and the pivot pin therefore trap each other in place on the movable contact supporting member so long as the pivot pin is in place. The U-shaped bracket, moreover, is received in notches or between opposed abutment portions in the movable contact supporting member, whereby relative longitudinal movement between the bracket and the contact supporting member is prevented without the necessity of positively aflixing the bracket to the contact supporting member. The pivot pin has its ends extending into holes in the main contact arm thereby pivotally supporting the contact supporting member on the contact arm. Barriers are also provided in the insulating casing for preventing the pivot pin from sliding axially out of its retained position.

The invention will be more fully understood from the following detailed description, and its scope will be pointed out in the appended claims.

In the drawings,

FIGURE 1 is a side elevation view, partially in section,

of an electric circuit breaker incorporating the invention, portions of the insulating casing also being broken away;

FIGURE 2 is an exploded perspective view of a contact arm assembly of FIGURE 1, and

FIGURE 3 is a sectional view of the circuit breaker of FIGURE 1, taken generally on the line 33 of FIG- URE 1.

Referring to FIGURE 1, the invention is shown as incorporated in an electric circuit breaker comprising an insulating casing 1 including a base 2 and a cover 3. The casing 1 is generally rectangular and includes three line terminals (not shown) at one end, and three load terminals (not shown) at the other end. Electrical continuity between each pair of corresponding line and load terminals is adapted to be controlled by a pair of contacts including a relatively movable contact 4 and a stationary contact 5 (only one pair shown).

Each of the movable contacts 4 is carried by a movable contact member or contact supporting member 6, which is pivotally connected to a generally channel-shaped contact arm 7 by pivot pin 14, in a manner to be described.

The forward end of the movable contact support 6 has a post 6A extending through a slot in the end of the contact arm 7. A compression spring 6A is positioned on post 6A between the support 6 and the arm 7, and a cotter pin 63, overlying a washer 6F, limits movement of the support 6 away from arm 7. The contact support 6 has a flexible connector 60 connected thereto adjacent the pivoted end, by suitable means such as by brazing.

The contact arm 7 for the center pair of line and load terminals, as illustrated in FIGURE 1, is pivotally supported on a pivot pin 8 passing through depending side portions 7 of the contact arm 7, and having its ends journalled in opposed side plate portions of a stationary frame assembly 9.

The contact arm 7 for each pair of line and load terminals is anchored by suitable fastening means 10 to a contact cross-arm 11 of reinforced insulating material. Movement of the center contact arm 7 therefore carries with it the two outer contact arrns also.

For the purpose of operating the contact arms 7 between open and closed circuit positions, operating mechanism is provided including a toggle linkage, comprising a pair of side-by-side upper toggle links 12 and a pair of lower toggle links 13, The lower toggle links 13 pass through slots 7A in the bight portion of the contact arm 7. Each of the lower toggle links 13 also includes an angularly extending portion 13A having an end portion 13A which is disposed and arranged to engage the pivot pin 8 when the parts are moved to the closed circuit position. The end 13A also engages the pin 8 when the parts move to a tripped position, for the purpose of retaining the toggle links 12 and 13 in a more collapsed condition than they would otherwise assume at such time. The construction of the circuit breaker mechanism, including toggle links such as 13, including an extending portion adapted to engage the pivot pin of the contact arm as described is disclosed and claimed in copending application Serial No. 210,641, Jencks and Murphy, filed July 18, 1962, and assigned to the same assignee as the present invention.

The upper toggle links 12 are connected to the lower toggle links 13 by a knee pivot pin 15. The upper toggle links 12 are also connected, by pivot pin 16, to a releasable support or cradle member 17. The cradle member 17 is pivotally supported at one end on the supporting frame 9 by pivot pin 18. The cradle member 17 is releasably latched at its other end by a suitable latch member 19. The latch member 19 is adapted to be moved, or permitted to move, to releasing position by suitable current responsive means, not shown.

The toggle linkage comprising links 12 and 13 is adapted to be operated between collapsed and straightened condieastern u) tions by means of a manually operable handle member 20, carried by a handle support member 21. The handle support member 21 is generally bifurcated or U-shaped, and is pivotally supported on the sides of the frame member 9 on pivot supports, not shown.

Movement of the handle member from the position shown in FIGURE 1 in the counterclockwise direction, moves the operating spring 22, which is connected between the handle support member 21 and the knee pin 15 of the toggle linkage, across the line of centers of pivot pins 15 and 16, and moves the toggle linkage from collapsed to straightened position, with a snap action. This moves the movable contact arms 7 to closed circuit position.

Upon the occurrance of predetermined current conditions through the contacts 4 and 5, the member 17 is released by latch 19, and the parts thereupon move to the tripped position. In so doing, the releasable member 17 moves counterclockwise, permitting the toggle assembly including links 12 and 13 to move upwardly and permitting the contact arms 7 and movable contact supports 6 to move in clockwise direction, moving the contacts 4 to open circuit position.

In accordance with the invention, and referring particularly to FIGURE 2, the movable contact member 6 is pivotally supported on the contact arm 7 by simple means requiring no separate fastening operation. Thus the movable contact support 6 is provided with a pair of opposed notches 6D adjacent the pivoted end thereof. A generally U-shaped bracket 3% is provided which is adapted to straddle the contact support member 6 and has opposed side portions 31 thereof received in the notches 6D. The side portions 31 are provided with aligned holes 32 adapted to receive the pivot pin 14. When in place, the pivot pin 14 extends across the member 6 on the side thereof opposite from the bight 33 of the U-shaped mem ber 36). The U-shaped member 50 and the pivot pin 14 therefore trap each other in place on the contact support member 6, when assembled. The notches 6D each comprise a pair of spaced abutment portions 6D which cooperate with the bracket to prevent relative longitudinal movement of the bracket 30 and the contact members 6 without the necessity of the bracket 38 being positively affixed to the contact member. The contact arm 7 also includes a pair of aligned holes 34 in the depending side portion 7' for receiving the end portions of the pivot pin 14, to thereby pivotally support the member 6 on the contact arm 7.

Referring to FIGURE 3, it will be observed that the side plates of the mechanism supporting frame 9 extend closely adjacent the ends of the pivot pin 14 of the center pole. The presence of the side plates limits axial sliding movement of the pin 14-, and retains it in proper engagement with the bracket 3% and contact arm 7.

For the purpose of retaining the pins 14 of the outer contact arms against axial sliding movement, snap-on washers or snap-rings 14A are provided on each end of the pins 14' just inside the corresponding wall 7' of the contact arm.

The assembly sequence of the parts is as follows: the bracket 30 is placed on the movable contact support 6, with the side portions 31 received in the notches 6D, and the bight portion 33 against the upper surface of the support member 6. These two parts, in this relation, are then placed within the U-shaped contact arm 7 so that the holes 32 are in alignment with the holes 34 in the side walls 7 of the contact arm 7. The pin 14 is then slid into place, through the aligned holes 32, 34, and on the opposite side of the contact support 6 from the bight 33 of the bracket 39. The pin 14 therefore holds all these parts in assembled relation.

All three contact arm assemblies of the circuit breaker are assembled in this manner and then the entire mechanism is mounted in place in the insulating base 2. As

previously mentioned, when the mechanism is in place in i the base 2, the barrier portions 35 extend closely adjacent the ends of each of the pins 14 and prevent sliding movement of the pins so as to become disengaged.

It will be seen that I have provided a movable contact arm assembly including a main contact arm and a movable contact carrying member pivotally supported thereon by means which is simply, effective, and dependable, and does not require the use of a metal working operation, such as welding, riveting, brazing, etc. or of a separate fastening operation, such as bolting.

While the invention has been described in connection with one particular embodiment, it will be readily appreciated that many modifications thereof may readily be made. Thus while a particular circuit breaker operating mechanism has been shown and described, any suitable switching mechanism may also be used to operate the movable contact arm assembly between open and closed position. It is therefore intended by the appended claims to cover all modifications as fall Within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric switching device including at least one movable contact and means for moving said movable contact between open and closed circuit positions comprising:

(a) a movable contact arm having a pair of spaced wall portions with aligned holes therein,

(b) an elongated contact member between said wall portions of said contact arm,

(0) a generally U-shaped bracket straddling said contact member, said bracket including opposed side portions having a pair of aligned holes therein in alignment with said holes in said side portions of said contact arm,

(d) a pivot pin passing through said aligned holes in said wall portions of said contact arm and said side portions of said bracket at the side of said contact member opposite from the bight of said bracket,

(e) means preventing relative longitudinal movement of said bracket and said contact member without positively affixing said bracket to said contact member, and

(f) means limiting axial sliding movement of said pivot pin relaive to said bracket to retain said pivot pin in engagement with said contact arm and said bracket.

2. An electric switching device including at least one movable contact and means for moving said movable contact between open and closed circuit positions comprismg:

(a) a movable contact arm having a pair of spaced wall portions with aligned holes therein,

(b) an elongated contact member between said wall portions of said contact arm,

(6) a generally U-shaped bracket straddling said contact member, said bracket including opposed side portions having a pair of aligned holes therein in alignment with said holes in said side portions of said contact arm,

(d) a pivot pin passing through said aligned holes in said wall portions of said contact arm and said side portions of said bracket at the side of said contact member opposite from the bight of said bracket,

(2) said contact member having at least one pair of opposed abutment portions disposed and arranged to engage corresponding portions of said bracket to prevent relative longitudinal movement of said bracket and said contact member without positively afiixing said bracket to said contact member, and

(1) means limiting axial sliding movement of said pivot pin relative to said bracket to retain said pivot pin in engagement with said contact arm and said bracket.

3. An electric switching device including at least one movable contact and means for moving said movable contact between open and closed circuit positions comprising:

(a) an insulating casing.

(b) at least one relatively stationary contact in said casing,

(c) at least one relatively movable contact in said casing,

(0!) operating mechanism for operating said relatively movable contact between open and closed circuit positions, said operating mechanism comprising a supporting frame having a pair of spaced side plates,

(e) a movable contact arm pivotally supported between said side plates of said supporting frame having a pair of spaced wall portions with aligned holes therein,

(1) an elongated contact member between said wall portions of said contact arm,

(g) a generally U-shaped bracket straddling said contact member, said bracket including opposed side portions having a pair of aligned holes therein in alignment with said holes in said side portions of said contact arm,

(h) a pivot pin passing through said aligned holes in said wall portions of said contact arm and said side portions of said bracket at the side of said contact member opposite from the bight of said bracket,

(i) said contact member having at least one pair of abutment portions engageable with said bracket to prevent relative longitudinal sliding movement of said bracket and said contact member without positively aflixing said bracket to said contact member,

( said side plates of said supporting frame being closely adjacent the said wall portions of said contact arm and limiting axial sliding movement of said pivot pin relative to said bracket to retain said pivot pin in engagement with said contact arm and said bracket.

4. An electric switching device including at least one movable contact and means for moving said movable contact between open and closed circuit positions comprising:

(a) an insulating housing,

(b) an elongated movable contact member in said housing,

(c) a generally U-shaped bracket straddling said contact member, said bracket including opposed side portions having a pair of aligned holes therein,

(d) a pivot pin passing through said aligned holes in said opposed side portions of said bracket at the side of said contact member opposite from the bight of said bracket,

(e) means preventing relative longitudinal movement of said bracket and said contact member without positively affixing said bracket to said contact member,

(f) means limiting axial sliding movement of said pivot pin relative to said bracket to retain said pivot pin in engagement with said contact arm and said bracket, and

(g) means supporting said pivot pin in said insulating housing at the portions thereof projecting beyond said bracket.

5. An electric switching device comprising:

(a) an insulating enclosure,

([2) a pair of spaced supporting members supported in said insulating enclosure, said supporting members having a pair of aligned holes therein,

(0) an elongated contact member between said supporting portions,

(d) a generally U-shaped bracket straddling said contact member, said bracket including opposed side portions having a pair of aligned holes therein in alignment with said holes in said supporting members,

(e) a pivot pin passing through said aligned holes in said supporting members and said holes in said side portions of said bracket at the side of said contact member opposite from the bight of said bracket,

(f) means preventing relative longitudinal movement of said brackets and said contact member without positively aflixing said bracket to said contact member, and

(g) means limiting axial sliding movement of said pivot pin relative to said bracket to retain said pivot pin in engagement with said contact arm and said bracket.

Jones Apr. 9, 7 

1. AN ELECTRIC SWITCHING DEVICE INCLUDING AT LEAST ONE MOVABLE CONTACT AND MEANS FOR MOVING SAID MOVABLE CONTACT BETWEEN OPEN AND CLOSED CIRCUIT POSITIONS COMPRISING: (A) A MOVABLE CONTACT ARM HAVING A PAIR OF SPACED WALL PORTIONS WITH ALIGNED HOLES THEREIN, (B) AN ELONGATED CONTACT MEMBER BETWEEN SAID WALL PORTIONS OF SAID CONTACT ARM, (C) A GENERALLY U-SHAPED BRACKET STRADDLING SAID CONTACT MEMBER, SAID BRACKET INCLUDING OPPOSED SIDE PORTIONS HAVING A PAIR OF ALIGNED HOLES THEREIN IN ALIGNMENT WITH SAID HOLES IN SAID SIDE PORTIONS OF SAID CONTACT ARM, 